Explained the "photoelectric effect" by proposing that light is both a wave and a particle
proposed that atoms accept ONLY specific amounts of energy called quanta
proposed that all matter is made up of atoms and established ideas about how atoms combine to form compounds in definite proportions.
proposed that electrons orbit the nucleus in circular orbits (solar system model)
positive and negative charges make up his plum pudding model.
determined the mass to charge ratio of an electron
discovered the nucleus
uses stopping voltage to determine the energy of electrons, and enabled Planck's constant to directly relate frequency to energy.
As energy increases, frequency______?
Which has lower energy? Red of Violet?
Distance between corresponding points on adjacent waves. Length of one complete wave.
number of waves that pass a point during a certain time period. Defined as the number of waves that pass a given point in a specific time (1 second)
distance from the origin to the trough or crest.
energy that is emitted in small specific amounts.
the emission of electrons from a metal when light shines on a metal.
Low energy waves have _____ frequencies.
Length of visible spectrum
Which has higher energy? Red or Violet?
bundles of light energy that is emitted by electrons as they go from higher energy levels to lower energy levels. Particle of electromagnetic radiation having zero mass and carrying a quantum of energy.
Each element has a unique bright-line emission spectrum
What is the significance of the Line Emission Spectrum?
Energy of a photon is ______ to its frequency.
what is frequency measured in?
what is energy measured in?
meters, nm, etc
what is wavelength measured in?
C=speed of light
region in space where there is 90% probability of finding an electron. "electron cloud"
Each orbital can hold___electrons
The S sublevel has____electrons
The S sublevel has___orbitals
The P sublevel has______orbitals
The P sublevel has_____electrons
The D sublevel has____orbitals
The D sublevel has____electrons
When the electrons falls to a lower energy level, a _____ is emitted.
Size of the orbital
What does the energy level tell you?
electrons fill the lowest energy orbitals first. An electron occupies the lowest-energy orbital that can receive it.
Pauli's Exclusion Principle
Each orbital can hold TWO electrons, but they must have opposite spins.
Within a sublevel,place one electron per orbital before pairing them up. "urinal analogy"
lowest energy state of an atom
a state in which an atom has a higher potential energy that it has in its ground state.
Principle quantum number
symbolized by n, indicates the main energy level occupied by the electron.
Angular momentum number
symbolized by l, indicates the shape of the orbital s-spherical p-dumbbell
Magnetic quantum number
symbolized by m, indicates the orientation of an orbital around the nucleus.
Spin quantum number
has only two possible values (+1/2, or -1/2) which indicate the two fundamental spin states of an electron in an orbital
As the wavelenght become shorter, the energy is______.
electrons orbit the nucleus in circular paths of fixed energy.
specify the "address" of each electron in an atom
electrons are found within a sphere around the nucleus
most appear to be the combination of two p-orbitals, "daisy"
orbital that look like "dumbbells or propellers" or tear drops.
really complicating structure.
# of sublevels per level
# of orbitals per level
All atoms of the same element are identical, other atoms are different. Proposed that atoms are small, uniformely dense, and indivisible.
Crooke & Thomson
used a cathode ray tube. Determined that atoms also contain witin themselves small negatively charged particles. They discovered the electron, the 'first' subatomic particle.
He tested Thomson's model with the gold foil experiment. According to Thomson's model, radiation particles should not be deflected. but in his experiment, some radiation was deflected.
Discovered the neutron. He reevaluates data and proposes that the radiation was actually a "massive" particle.
will only accept energy in small 'quantized' packets.
Applied wave-particle theory to electrons. Found that electrons exhibit wave properties.
The wavefunction helps describes the location of the electron, and its probable location. Electrons have a wavelenght.
Ion electron configuration
write the electron configuration for the closest Noble Gas
Atoms gain or lose electrons to become more stable.
Heisenberg Uncertainty Principle
impossible to know both the velocity and position of an electron at the same time.
Pauli Exclusion Principle
no to electrons in an atom can have the same 4 quantum numbers.